This monograph reviews literature pertaining to children without permanent parents. Chapters review (1) the development of children while institutional residents; (2) the development of postinstitutionalized children transitioned to family environments (i.e., adoption); the effects of institutionalization on (3) attachment behaviors, (4) physical growth, and (5) neurobiological development; (6) the possibility of a sensitive period in early development during which institutionalization may be most damaging; (7) best practices in low-resource countries in moving toward family alternatives to institutions; (8) challenges faced by these countries in formulating and implementing such policies; and (9) more speculative interpretations of major research, practice, and policy issues in this field. It is clear that: (1) Infants and young children being reared in most institutions are substantially delayed in their physical, neurobiological, cognitive, and social-emotional development; (2) If such children are transitioned to family environments (e.g., adoptive, foster families), immediate and substantial catch-up growth is observed in all domains; (3) However, deficiencies and problems in all developmental domains can persist at higher than expected rates even after transitioning to families, especially in children leaving the institution after 6-24 months depending on the severity of the depriving institutional conditions, the particular developmental outcome and measure, and other factors; (4) Family alternatives generally provide better rearing environments for young children than institutions and usually at less cost; (5) Many children in institutions have one or both parents, who with financial and social support could retain their children. Ideally, others should be transitioned to family alternatives as early in life as possible. Institutions could be improved to enhance the development of children who must remain in their care because of lack of alternative arrangements, special needs, and health status (e.g., HIV); and (6) Child welfare systems that operate within a children's rights framework are preferred, but there are a variety of historical, cultural, political, administrative, and financial challenges to implementing such systems. This volume is a synthesis of empirical research on the development of children without permanent parents that contributes to scholarship on the effects of early experience on development. In addition, it provides a basis of evidence that supports changes in practice and policy that promote better rearing environments worldwide for these children consistent with international agreements concerning the rights of all children. (Contains 8 tables, 1 figure, and 4 notes.)